Telecommunication networks are evolving from the use of circuit switched technologies to the use of packet based technologies such as the Internet Protocol (IP). As network infrastructures begin to support such packet technologies, protecting network services from security attacks is becoming an increasingly important issue. One reason for this is that packet networks tend to be more vulnerable to attacks than traditional circuit-switched networks. For example, Voice over IP (VoIP) is a voice communication technology that uses an IP based infrastructure, and voice communications in IP-based networks that use VoIP technology may be susceptible to security attacks such as voice spam or denial of service.
Emergency response services, commonly known as E911 service in the United States, provide an important function that needs to be protected from spam or other packet based attacks. If not protected, voice spam and other security attacks may render an emergency response service unavailable. Generally, one of the challenges in providing emergency response services is that such services should ideally be available to all terminals and users when needed. In addition, due to the urgency of many emergency response service requests, delays in fulfilling a request should be minimized. Current methods and systems do not adequately meet these and other needs, and improvements are needed in protecting emergency response services in networks using packet based technologies.